The "literal" part: Googling "object literal" provides two top resources: MDN and Wikipedia. To quote the latter:

In computer science, a literal is a notation for representing a fixed value in source code. Almost all programming languages have notations for atomic values such as integers, floating-point numbers, and strings, and usually for booleans and characters; some also have notations for elements of enumerated types and compound values such as arrays, records, and objects.

Basically, all syntax constructs whose use lead to a defined type can be called a literal. (E.g., a string literal, "abc".) It's a technical term that denotes, that "literally" writing something in this or that way leads to a certainly typed variable exclusively (in contrast to constructs, that look like something else, like array() in PHP).

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